1. Field of the Invention
The field of the invention is that of tapping attachments, that is, components which carry a tap for threading holes and which are driven by some type of driving machine.
2. Description of the Prior Art
The field of the invention is exemplified by prior art patents of the herein inventor, including U.S. Pat. Nos. 3,397,588, 3,472,347; 3,717,892; 3,946,844; 3,999,642; 4,014,421; 4,029,429; and 4,067,424.
The prior art patents deal with tapping attachments which have a body and a drive spindle which carries the tap. The body of the attachment is driven by some form of driving machine, and drive is imparted from the body to the spindle. The prior patents relate in part to the clutching means as between the body and the spindle for direct drive and also for reverse drive.
The prior art patents do not embody certain improvements which are present in the herein invention which are particularly adapted to what may be called attachments for heavy duty and which are outlined more specifically hereinafter.
A further characteristic which is not present in the prior art patents is that of providing for relative axial extension of the tapping spindle and the tap which is held by it. The nature of these characteristics or improvements which are not present in the prior art patents is explained in detail hereinafter.
With respect to the prior art, in the prior art an attempt has been made to provide for a flow of coolant using a coil of flexible plastic tube but, of course, in a direct drive machine, it involves rotation in only one direction, so that this has not been done in a reversible type of attachment.
In addition, in the prior art provision has not been made for a flow of coolant at high pressure through the use of flexible tube associated with coolant flow for use in a reversible type of tapping attachment.